Homopolymerization of Methyl Methacrylate by NovelZiegler-Natta-Type Catalysts Based on Bis(chelate)-nickel(II) Complexes and Methylaluminoxane

Communication: Novel catalytic systems based on bis- (chelate)nickel(II) precursors, such as bis(a-nitroacetophenonate) nickel(II) [Ni(naph)2] and bis(2,6-diisopropylbenzenesalicylaldiminate) nickel(II) [Ni(dipbs)2], and methylaluminoxane (MAO) as the cocatalyst were employed for the polymerization of methyl methacrylate (MMA). Reaction parameters were examined. Under proper conditions, the Ni(dipbs)2/MAO system allowed to obtain poly(MMA) with a very high productivity (TOF up to 70000 h± 1) and a remarkable syndiospecificity degree (rr A 80%) at room temperature without addition of an ancillary Lewis base